Presses of the aforementioned type are known for example from DE 10 2011 116 548 A1, DE 10 2011 116 552 A1 or EP 2 479 022 A1, the entire contents of which are hereby incorporated by reference. In known presses, a drive axle has at least two spindles with corresponding spindle nuts. The spindle nuts can be interconnected via a force transmission bridge. The force transmission bridge is moved by the spindle drives in the vertical direction and acts on the upper or respectively lower die, in particular via suitable die plates. It was also already suggested to provide for example flexible compensation elements between the spindle nuts and the force transmission bridge. The compensation elements ensure that a potential tipping or bending of the force transmission bridge is not transmitted to the spindle drives. In particular, the spindle drives should continue to be aligned strictly vertically. The spindle drives are operated as synchronously as possible in relation to each other during the pressing process. In this manner, a good pressing result is achieved for common pellets.
However, it is sometimes desired to produce pellets that are shaped in a very wide or very long manner or for example in a wedge-shaped manner. The required pressing force can then be asymmetrical over the elongation of the pellet. A thereby caused asymmetrical load is absorbed via the tool guiding frame. This can lead to tippings for example of the die plates or of the force transmission bridges. Increased wear is hereby caused, in particular with respect to the pressing unit having the upper and/or lower dies. Moreover, such a tipping has a disadvantageous impact on the pressing result.
Based on the explained state of the art, the object of the invention is to provide a method of the initially named type with which wear can be reduced and the pressing result can be optimized independently of the pellet shape.